How to test if a class reference implements an interface?

How can I test if a class reference implements an interface?

Note that the is and instanceof operators do not work with Class references.

Example:

    public function set someClassref(value:Class):void
    {   
        if(value is IMyInterface)
        {
            _someClassref = value;
        }
        else
        {
            //
        }
    }

AS3 - Can I know if a class implements an interface (or is a subclass of another class)? has what appear to be the two most common solutions.